Local crystallization of glasses in the La2O3-B2O3-GeO2 system under laser irradiation

A method is proposed for local crystallization of glasses under laser irradiation. This method makes it possible to nucleate and grow microcrystals with a size distribution similar to a monodisperse distribution for several fractions of a second in any glass region chosen in advance. It is demonstrated using glasses in the La₂O₃-B₂O₃-GeO₂ system as an example that the crystallization of the stillwellite-like phase LaBGeO₅ with the composition close to the composition of the initial glass is observed in the glass under irradiation with the copper vapor laser operating in the high-speed pulse modulation mode. Strips (up to ～300 μm) produced at a specified depth from the glass surface contain extended regions consisting of uniformly distributed crystals, which have almost identical sizes, exhibit a pronounced faceting, and are identified using X-ray diffraction. The size and the number of crystals can be changed over a wide range by varying laser treatment conditions. This opens up the way to the design of new glass-ceramic materials in which the location of the crystalline phase in the glass bulk is controlled by a developer.